Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

[Rocky_H]

I want to make sure that BMS calibrates appropriately (even though that’s just a visual thing for the most part) AND that I keep the battery in the best health possible.

Pick one.
You are asking what to do to accomplish _____ AND _____. But those are at cross purposes, and the charging behaviors you would use for those two things are the exact opposite!

For the first thing you're asking, more accurate calibration, you would want to continually run it from very high to very low, so the BMS can see the range of it fully. But that is harsh on the health of the battery.

For the second thing you're asking, the healthiest thing thing for the battery is using a smaller range in the middle of the state of charge. But that is going to cause the estimate to get a bit fuzzy and inaccurate.

So these threads never stop, where people continually ask what they should do but are always wanting those two opposite things.

 

[andy92782]

I track my car with Teslamate. My projected range really took a nosedive over the past couple months. No change in driving behavior. I'm now down to ~267 @ 100%. Can't say I'm thrilled about this.

 

[DougWantsALeaf]

Welcome to your new and now normal baseline range. 10% loss after a couple years is quite the norm.

 

[Candleflame]

Extremely high degradation in just few weeks of use. 3-5% in a year is fine, 6% in little over 2 months is bad.


16Km so far, in just 2 months. Brand new was showing 570 at 100% ... now it is showing 554 at 100% and that value is decreasing with 1 Km every few days, after almost every charging session ... even if I charge 20-60%.

16km after 2 months is normal. Nothing to worry about.

 

[ro_explorer]

Well, I do not consider it normal at all. This is a real life application of the saying "your mileage might vary" ...
On a serious note, it is too much, too soon.

 

[Candleflame]

Well, I do not consider it normal at all. This is a real life application of the saying "your mileage might vary" ...
On a serious note, it is too much, too soon.

that is an entirely different debate i.e. if manufacturers should advertise average/median degradation.

Newer cars dont hide any degradation. But losing essentially 2% in the first 2 months is completely normal.

 

[ro_explorer]

losing essentially 2% in the first 2 months is completely normal.

I completely agree to this. Still 76kWh compared to 80Kwh (after 2 months) is not 2% ... it is 5%. See my problem?

 

[Candleflame]

I completely agree to this. Still 76kWh compared to 80Kwh (after 2 months) is not 2% ... it is 5%. See my problem?

i think losing rated range is more indicative than kwh with the newer batteries... Rated range gives you a better indication of what the BMS thinks the capacity is as rated range is just a direct reflection of range. you have 2%, not 5%. from your range drop and the kwh it seems more that you have a 78.8kwh battery anyway.

 

[Candleflame]

I completely agree to this. Still 76kWh compared to 80Kwh (after 2 months) is not 2% ... it is 5%. See my problem?

just fyi i was down 11km from 499km starting range after a couple of months too. That is 2.3%.

 

[ro_explorer]

No my friend .. SMT is reading the BMS directly. That is the actual capacity of the battery. That is the actual loss.
The rated range starts decreasing once the actual capacity goes below the 100% threshold capacity. So, yes, I lost 2% rated range, but I lost 5% from the battery capacity ... and this is bad, in my opinion. If is gonna stay like this for the next 6 months or so, good ... but I highly doubt it. It is never a good sign when the battery capacity is plummeting, especially as new.

 

[Candleflame]

No my friend .. SMT is reading the BMS directly. That is the actual capacity of the battery. That is the actual loss.
The rated range starts decreasing once the actual capacity goes below the 100% threshold capacity. So, yes, I lost 2% rated range, but I lost 5% from the battery capacity ... and this is bad, in my opinion. If is gonna stay like this for the next 6 months or so, good ... but I highly doubt it. It is never a good sign when the battery capacity is plummeting, especially as new.

No my friend. your car lost 2% of its rated range. If you had extra capacity it was an added bonus. and you will lose another 8% or so over the next 2 years.

 

[ro_explorer]

and you will lose another 8% or so over the next 2 years.

That would be OK.

If you had extra capacity it was an added bonus.

Yes, but it was my bonus, my capacity ... and it is gone prematurely.

I'll stop here ... this is going nowhere. I think you understood my point by now.

 

[derotam]

Yes, but it was my bonus, my capacity ... and it is gone prematurely.

While I understand your point, it is a little unreasonable from the rated range of the vehicle standpoint. You bought the vehicle with x range and that is what you as the consumer should expect to receive, with the standard allowable degradation.

You seem to be complaining about losing the extra capacity that a manufacturer might add in order to dull the user facing degradation(in range).

Now here is where the fun begins... The battery warranty. Tesla is warranting CAPACITY, not range, so because of that you can use that 5% value...BUT, you are still in warranty so....sorry. Unfortunately but understandably, Tesla does now warrant a specific degradation curve rate, it's just 70% at 8 years(100/120k miles). Also, Tesla doesn't define "Capacity". Is that the specific capacity of the specific pack that was put in your car? Is it a "standard" capacity value assigned to a model/year of cars? Who knows.

Anyway as is the standard here, some batteries are above the curve, some below, and some in the middle...looks like you are below the curve a bit, sorry.

 

[AlanSubie4Life]

That would be OK.

Yes, but it was my bonus, my capacity ... and it is gone prematurely.

I'll stop here ... this is going nowhere. I think you understood my point by now.

I completely agree to this. Still 76kWh compared to 80Kwh (after 2 months) is not 2% ... it is 5%. See my problem?

To be fair, you started at 79.2kWh or so, so it's "only" 4%. Which is certainly not ideal in the timeframe you have experience it, and well outside the norm in that timeframe. They are estimates though, and there is in a SHORT timeframe a chance that the estimate will bounce back (though of course the overall trend will definitely be down). It can take some time to adjust back from a low CAC estimate.

Or, it's possible your initial 79.2kWh reading was optimistic, and it is just adjusting down the estimate to the "correct" value with time (hard to know without the specifics).

During the first week of ownership I received my bluetooth dongle and I was able to hook up SMT to it. At that time (probably 300 Km or so of driving with it, barely on second charge) the Nominal full pack parameter was showing 79.2 kwh.

 

[andy92782]

Welcome to your new and now normal baseline range. 10% loss after a couple years is quite the norm.

I get that, but I don't get why it's been falling off so rapidly over the past couple months as opposed to a more gradual decline.

 

[Toneus]

I track my car with Teslamate. My projected range really took a nosedive over the past couple months. No change in driving behavior. I'm now down to ~267 @ 100%. Can't say I'm thrilled about this.

View attachment 700957

I too have noticed a down tick in my Teslamate Projected Range since late July. We saw our summer turn on the heat around then, so I hope it's a weather/temperature bias that they overcooked and the "more accurate range" calculation is the reason behind the trend, OR an updated Avg Wh/mi denominator now that we're using A/C more aggressively.

 

[Kingman514]

I pick up my model 3 performance next week. I have to make a short trip to shreveport, la from Dallas, Tx. ABRP shows it takes 96% of a full battery to go 196 miles. Tesla trip planner is about the same. Is the range really that poor of a Tesla? Especially when this Model 3 advertises a 315 mile range. This is really bothering me?

 

[jmaddr]

Welcome to Tesla gaming the EPA test cycle (as well as every other car company).

The range now quoted is based on the EPA tested reference consumption of about 245Whr/mi. You can achieve that at around the EPA average of around 50 mph or hanging out behind a truck abit faster. At more realistic speeds, say about 75-80 mph, I’m running 310-340 Whr/mi depending on hills, rain, weight, temperature, and wind. ABRP and others allow you to manipulate these things so see how these are set on ABRP on your side.

I have a 2109 so a slightly smaller battery, but I get low 220-240s per 100 percent equivalent depletion.

 

[Gauss Guzzler]

@Kingman514 You can expect better than 300Wh/mi when cruising on a straight fast highway so with about 80kWh battery capacity the range would be 80,000/300 = 267 miles. That's not far out of line from the EPA specs considering you'll be cruising at 80-90mph rather than the EPA assumption of mixed city/highway.

Be sure to remind the delivery center to charge your car before you arrive otherwise they'll just give it to you dead like they did to me. They are profoundly lazy and shamefully unaware of how electric cars work, or even how basic retail works.

Anyway, when you get the car just tell it your destination and it will show a remarkably accurate prediction of your estimated battery state upon arrival. The estimate will continuously update as you drive and you can decide whether or not to stretch your legs for 5-10 minutes at the Lindale Supercharger. Hopefully you used someone's referral code to get 6 months of free charging, if not, ask for mine as it might not be too late.

 

[KenC]

I pick up my model 3 performance next week. I have to make a short trip to shreveport, la from Dallas, Tx. ABRP shows it takes 96% of a full battery to go 196 miles. Tesla trip planner is about the same. Is the range really that poor of a Tesla? Especially when this Model 3 advertises a 315 mile range. This is really bothering me?

Does it matter? Stop in Lindale and supercharge for 5 mins. It's nearly 100 degrees, and there's a 10mph headwind.